macOS Quick basic question about functions in Fortran

[Spanky Deluxe]

Hi guys,

I'd like to split up my fortran program into several functions but I need to be able to pass arrays to these functions.

Right now I've got this:

PROGRAM test1
IMPLICIT NONE
	...
	real x(maxpoints), y(maxpoints), z(maxpoints)
	...
END PROGRAM test1

FUNCTION distance(x, y, z)
	write(*,*) 'Hello'
END FUNCTION distance

I realise this isn't right but I don't know what I'm supposed to be doing with functions - I was told that Fortran deals with memory and arrays very differently to C which I'm used to.

x, y and z are arrays of a certain length which need to be acted upon in the function.

Can anyone help?